Browsing Research Output by Author "10059539 - Van Rooyen, Johannes Marthinus"
Now showing items 1-20 of 96
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8-Oxo-7,8-dihydro-2’-deoxyguanosine, reactive oxygen species and ambulatory blood pressure in African and Caucasian men: the SABPA study
Mels, C.M.C.; Schutte, A.E.; Schutte, R.; Pretorius, P.J.; Smith, W.; Huisman, H.W.; Van der Westhuizen, F.H.; Fourie, C.M.T.; Van Rooyen, J.M.; Kruger, R.; Louw, R.; Malan, N.T.; Malan, L. (Taylor & Francis, 2014)Various studies indicate a relationship between increased oxidative stress and hypertension, resulting in increased DNA damage and consequent excretion of 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG). The aim of this study ... -
Adipokines and cardiometabolic function: how are they interlinked?
Schutte, Aletta Elisabeth; Huisman, Hugo Willem; Schutte, Rudolph; Van Rooyen, Johannes Marthinus; Malan, Leoné; Fourie, Catharina Maria Theresia; Malan, Nicolaas Theodor (Elsevier, 2010)Objective Adipokines contribute directly to the coexistence of insulin resistance and endothelial dysfunction. Most studies focus on a single adipokine. We therefore investigated the independent relationships of leptin, ... -
The African prospective study on the early detection and identification of cardiovascular disease and hypertension (African-PREDICT): design, recruitment and initial examination
Schutte, Aletta E.; Uys, Aletta S.; Burger, Adele; Mels, Catharina M.C.; Kruger, Ruan; Smith, Wayne; Fourie, Carla M.T.; Botha, Shani; Lammertyn, Leandi; Van Rooyen, Johannes M.; Gafane-Matemane, Lebo F.; Mokwatsi, Gontse G.; Breet, Yolandi; Kruger, H. Salome; Van Zyl, Tertia; Pieters, Marlien; Zandberg, Lizelle; Louw, Roan; Moss, Sarah J.; Huisman, Hugo W. (Sage, 2019)Background: Globally hypertension is stabilising, but in sub-Saharan Africa the incidence of hypertension remains on an increase. Although this might be attributed to poor healthcare and ineffective antihypertensive ... -
Agreement between specific measures of adiposity and associations with high blood pressure in black South African women
Kruger, Herculina S.; Botha-Ravyse, Chrisna; Havemann-Nel, Lize; Doubell, Maretha; Van Rooyen, Johannes M. (Wiley, 2017)Objectives To derive percentage body fat (%BF) cut-points according to body mass index (BMI) categories for adult black South African women and to investigate the agreement between adiposity classifications according to ... -
Alcohol intake, hypertension development and mortality in black South Africans
Zatu, Mandlenkosi C.; Van Rooyen, Johannes M.; Kruger, Annamarie; Schutte, Aletta E. (Sage Publishing, 2016)Background: Excessive alcohol intake is a risk factor for cardiovascular disease (CVD) and predicts cardiovascular and all-cause mortality. We determined which alcohol marker (self-reported alcohol intake, gamma-glutamy ... -
Aldosterone and renin in relation to surrogate measures of sympathetic activity: the SABPA study
Gafane-Matemane, Lebo F.; Van Rooyen, Johannes M.; Schutte, Rudolph; Schutte, Aletta E. (Clinics Cardive Publishing, 2019)Introduction: Hypertension, particularly in black populations, is often accompanied by augmented sympathetic nervous system activity and suppressed renin activity, indicative of possible blood pressure (BP) dysregulation. ... -
Alkaline phosphatase and arterial structure and function in hypertensive African men: the SABPA study
Schutte, R.; Huisman, H.W,; Malan, L.; Van Rooyen, J.M.; Smith, W. (Elsevier, 2013)Background: Vascular calcification is believed to be due to the conversion of vascular smooth muscle cells into osteoblast-like cells and is associated with mortality. Since hypertension and related mortality in Africans ... -
Are behavioural risk factors to be blamed for the conversion from optimal blood pressure to hypertensive status in black South Africans? A 5-year prospective study
Schutte, Rudolph; Schutte, Aletta E.; Huisman, Hugo W.; Van Rooyen, Johannes M.; Fourie, Carla M.T. (Oxford University Press, 2012)Background Longitudinal cohort studies in sub-Saharan Africa are urgently needed to understand cardiovascular disease development. We, therefore, explored health behaviours and conventional risk factors of African individuals ... -
Arterial stiffness profiles: investigating various sections of the arterial tree of African and caucasian people
Huisman, Hugo Willem; Malan, Nicolaas Theodor; Schutte, Aletta Elisabeth; Schutte, Rudolph; Van Rooyen, Johannes Marthinus; Malan, Leoné; Reimann, Manja (Informa healthcare, 2011)In Africans, arterial stiffness progression seems more pronounced compared to Caucasians. We compared the arterial stiffness profiles of different age groups and focused on muscular arteries and two more central arterial ... -
Arterial stiffness, ambulatory blood pressure and low-grade albuminuria in non-diabetic African and caucasian men: the SABPA study
Schutte, Rudolph; Schutte, Aletta E.; Huisman, Hugo W.; Glyn, Matthew C.P.; Van Rooyen, Johannes M.; Malan, Nicolaas T.; Fourie, Carla M.T.; Malan, Leoné (Nature Publishing Group, 2011)Recent evidence suggests that low-grade urinary albumin excretion is a marker of early general attenuation of vascular function, but studies are limited to Caucasian population groups. We compared low-grade urinary albumin ... -
Assessing tobacco use in an African population: serum and urine cotinine cut-offs from South Africa
Ware, Lisa J.; Kruger, Ruan; Breet, Yolandi; Van Rooyen, Johannes; Huisman, Hugo; Botha, Shani; Uys, Aletta S.; Schutte, Aletta E. (Elsevier, 2019)Background Cotinine, a nicotine metabolite, is used to measure tobacco use and exposure, but recommended cut-offs to differentiate tobacco users from those exposed through the environment range from 3 to 58 ng/ml in serum, ... -
Association between blood pressure, measures of body composition and lifestyle factors in township adolescents, North-West Province, South Africa
Kruger, Herculina Salome; Mamabolo, Ramoteme Lesley; Monyeki, Makama Andries; Schutte, Aletta Elisabeth; Van Rooyen, Johannes Marthinus (LAM Publications, 2011)Risk factors for development of cardiovascular disease develop early in life and track into adulthood. This study investigated the relationship between blood pressure (BP) and measures of body composition in adolescents. ... -
The association of 25(OH)D with blood pressure, pulse pressure and carotid–radial pulse wave velocity in African women
Kruger, Iolanthé M.; Schutte, Aletta E.; Huisman, Hugo W.; Van Rooyen, Johannes M.; Schutte, Rudolph; Malan, Leoné; Malan, Nicolaas T.; Fourie, Carla M.T.; Kruger, Annamarie (Public Library of Science, 2013)High susceptibility of the African population to develop cardiovascular disease obliges us to investigate possible contributing risk factors. Our aim was to determine whether low 25(OH)D status is associated with increased ... -
The association of measures of the micro- and macro-vasculature with selenium and GPx activity in a young bi-ethnic population: the African-PREDICT study
Swart, Rijané; Schutte, Aletta E.; Van Rooyen, Johannes M.; Smith, Wayne; Mels, Catharina M.C. (Taylor & Francis, 2019)Objective: Selenium plays an important physiological role as component for antioxidant selenoproteins such as glutathione peroxidase (GPx). Since oxidative stress contributes to hypertension development, it is likely that ... -
The Association of Red Blood Cell Counts with Endothelin-1 in African and Caucasian Women
Huisman, Hugo W.; Schutte, Aletta E.; Van Rooyen, Johannes M.; Schutte, Rudolph; Malan, Leoné; Fourie, Catharina M.T.; Malan, Nicolaas T. (Informa Healthcare, 2009)The literature shows an increase in endothelin-1 with increased levels of erythrocytes. There are also indications that inflammation and elevated endothelin-1 levels interact with erythropoiesis. In this study, the association ... -
Associations between reactive oxygen species, blood pressure and arterial stiffness in black South Africans: the SABPA study
Kruger, R.; Schutte, R.; Huisman, H.W.; Van Rooyen, J.M.; Malan, N.T.; Fourie, C.M.T.; Louw, R.; Van der Westhuizen, F.H.; Van Deventer, C.A.; Malan, L.; Schutte, A.E. (Springer Nature, 2012)Many mechanisms, including oxidative stress, contribute to hypertension. This study investigated the possible associations between oxidative stress, blood pressure and arterial stiffness in black South Africans. Ambulatory ... -
Associations of cholesterol and glucose with cardiovascular dysfunction in black Africans: the SABPA study
Lammertyn, Leandi; Schutte, Rudolph; Schutte, Aletta E.; Huisman, Hugo W.; Van Rooyen, Johannes M.; Malan, Nicolaas T.; Fourie, Carla M.T.; Malan, Leoné (Informa healthcare, 2011)The aim was to determine whether blood glucose or cholesterol is the more prominent contributor to cardiovascular dysfunction in 101 African men and 99 African women. We measured ambulatory daytime blood pressure (BP), ... -
Asymmetric dimethylarginine and symmetric dimethylarginine prospectively relates to carotid wall thickening in black men: the SABPA study
Mels, Catharina M.C.; Schutte, A.E.; Huisman, H.W.; Smith, W.; Kruger, R.; Van Rooyen, J.M.; Malan, N.T.; Malan, L. (Springer, 2017)The relationship of both asymmetric (ADMA) and symmetric (SDMA) dimethylarginine with carotid wall thickness is inconclusive especially among black populations. We aimed to compare carotid intima media thickness (cIMT) and ... -
Attenuated NOx responses and myocardial ischemia, a possible risk for structural vascular disease in African men: the SABPA study
Uys, A.S.; Malan, L.; Van Rooyen, J.M.; Steyn, H.S.; Reimann, M. (Nature Publishing Group, 2014)Chronically elevated blood pressure has been associated with impaired NO-mediated vasodilation and structural vascular disease risk. This study aimed to determine whether significant associations exist regarding NO metabolite ... -
Baroreceptor sensitivity, cardiovascular responses and ECG left ventricular hypertrophy in men: the SABPA study
Steyn, Hendrik Stefanus; Van Rooyen, Johannes Marthinus; Van Lill, Lisa; Malan, Leoné; Reimann, Manja; Ziemssen, Tjalf (Informa Health care, 2011)Aim. Research has shown a significant relationship between hypertension and attenuated baroreceptor sensitivity (BRS), which in turn reflects alterations of autonomic control of the cardiovascular system. The objective of ...